The present invention relates to the generation of microorganism control compositions and the use thereof. In a more specific aspect, the present invention relates to a method of treating a body of fluid containing microorganisms in order to control such microorganisms.
In a number of industrial and municipal operations, the presence of microorganisms in bodies of fluid cause innumerable problems. For example, the growth of microorganisms in bodies of fluid often results in the plugging of structures into which or through which such fluid is to be passed, accumulation in the structures and thus reduction of fluid flow and, to the extent that small amounts of water are present, serious corrosion problems. Accordingly, it is common practice to employ microorganism control compositions to kill the microorganisms, or at least, prevent their rate of growth. Numerous microorganism control compositions are known for this purpose. However, such known microorganism control compositions, in many cases, are prohibitively costly to manufacture and are not available to remote locations where needed and are fraught with numerous problems in the handling and use thereof.
A particularly effective microorganism control material is hydrogen peroxide. However, the problems associated with the manufacture and use of hydrogen peroxide severely limit its use, particularly for the treatment of large bodies of fluid. While pure solutions of hydrogen peroxide, completely free of contaminants, are highly stable, such pure solutions are expensive and their purity almost impossible to maintain. On the other hand, concentrated solutions are highly toxic and strong irritants. In addition, in solution, hydrogen peroxide decomposes into water and oxygen, which decomposition is accelerated by the presence of impurities. Since solid hydrogen peroxide is explosive, there is always the danger of fire and explosion in the event attempts are made to utilize the same in this form, as well as in solution.
As previously indicated, the expense of utilizing hydrogen peroxide is a major factor. This is due to a complexity of commercial methods for manufacture and separation of the hydrogen peroxide. One common method is the autooxidation of an alkylanthrahydroquinone, such as the 2-ethyl derivative, in a cyclic continuous process in which the quinone formed in the oxidation step is reduced to the starting material by hydrogen in the presence of a supported paladium catalyst. A second technique involves electrolytic processes in which aqueous sulfuric acid or acidic ammonium bisulfate are converted electrolytically to the peroxybisulfate which is then hydrolyzed to form hydrogen peroxide. A third method is the autooxidation of isopropyl alcohol. Of these techniques, the first mentioned is the most widely utilized. It is also known that hydrogen peroxide can be produced as a by-product by the autooxidation of paraffinic hydrocarbons, such as propane, to produce olefins. Efforts have been made to maximize the production of hydrogen peroxide in this type reaction. However, no known commerical process utilizes this type of reaction and, hence, it has remained a laboratory curiosity.
Another effective microorganism control material is glutaraldehyde. This material is widely used where large bodies of fluids are to be treated, such as flood waters, for the recovery of oil, due primarily to its lower cost than other microorganism control materials, its effectiveness is relatively small amounts, its nonflammability and the ability to handle the same in relatively high concentrations. However, glutaraldehyde is toxic and an irritant and, therefore, reasonable care must be taken in the manufacture and handling of the same. Other aldehydes which are effective microorganism control materials include formaldehyde and aceteldehyde. These materials are also toxic and an irritant and, thus, care in the manufacture and handling is necessary and formaldehyde is a gas and polymerizes readily, thus, requiring the addition of inhibitors, such as methanol, to aqueous solutions but these materials have lower fire risks than hydrogen peroxide or glutaraldehyde. Ketones, such as acetone, and ethers, such as propylene oxide, esters, etc. also act as microorganism control materials. However, both acetone and propylene oxide are highly flammable but are moderately toxic and irritant. The above-mentioned disadvantages of the aldehydes, ketones, ethers and esters thus require care in the manufacture and handling of the same and must be transported as solutions. For example, glutaraldehyde is available in aqueous solutions of 50% and 25% by volume and formaldehyde is commercially available in concentrations of 37% to 50% in an aqueous solution containing up to 15% methanol as a polymerization inhibitor. Accordingly, while glutaraldehyde is effective as a microorganism control material in concentrations of about 10 to 50 parts per million by volume, it is necessary to transport substantial amounts of water along with the active agent. This is particularly troublesome where the material is to be utilized in large volumes, as in the treatment of waterflood waters, and particularly where it is to be utilized at remote locations, such as offshore production platforms.
Summarily, as previously indicated, the utilization of microorganism control materials, particularly hydrogen peroxide and aldehydes, in the treatment of large bodies of fluid becomes a rather expensive proposition since large amounts of microorganisms control materials are necessary. For example, in the treatment of water utilized for the displacement of oil in oil field operations, the treatment of pipeline slurries flowing through a pipeline and other industrial operations the cost becomes a significant factor and the availability of microorganism control materials at the location where needed further emphasize the problems in their use. It is common practice in the recovery of oil to inject water into an oil bearing formation to displace additional amounts of oil after the natural drive energy of the reservoir has dissipated. However, the presence of microorganisms, particularly sulfate-reducing bacteria, in the flood water causes serious problems of plugging of the oil bearing formation and corrosion of injection and downhole equipment. Consequently, it is necessary in such cases to kill the microorganisms, or at least retard their growth, to prevent or reduce these problems.